Diablo: finished

Got most spells, got decent equipment, killed Diablo on normal, The End. I can start a new game with the same character, but what difficulty level is it now? Going into the dungeon, monsters and loot seem weak, so I don't think I'm in Nightmare mode - I think you need to be running a multiplayer game for that, and I don't think there's any way of switching your single-player character over. Researching...

It looks like single-player was never meant to go on to Nightmare or Hell difficulty; you need to be using a multi-player character for that. This actually turned out well, because if I could go on, I probably would, and there's really no need. I've seen it, I remember it, I experienced it, and it was great when it came out, and its still good now, but its time to move forward. And there's still Diablo 2 to play.